Use of magnetic resonance imaging for evaluation of therapeutic response in breast cancer-related lymphedema: A systematic review

Identifying Functional Lymph Nodes in Lower Extremity Lymphedema Patients: The Role of High-frequency Ultrasound

BACKGROUND

 Lymph nodes may play a potential role in lymphedema surgery. Radiologic evaluation of nodes may reveal the status of pathologic conditions but with limited accuracy. This study is the first to evaluate the efficacy of ultrasound in detecting functioning nodes in lymphedema patients and presents a criterion for determining the functionality of the lymph nodes.

METHODS

 This retrospective study reviews 30 lower extremity lymphedema cases which were candidates for lymph node to vein anastomosis. Lymphoscintigraphy and magnetic resonant lymphangiography (MRL) imaging were compared with ultrasound features which were correlated to intraoperative indocyanine green (ICG) nodal uptake as an indication of functionality.

RESULTS

 Majority were International Society of Lymphology stage 2 late (50.0%) and stage 3 (26.7%). ICG positive uptake (functioning nodes) was noted in 22 (73.3%), while 8 patients (26.6%) had negative uptake (nonfunctioning). Ultrasound had significantly the highest specificity (100%) for identifying functional nodes followed by lymphoscintigraphy (55%) and MRL (36%; p = 0.002, p < 0.001, respectively). This was associated with 100% positive predictive value compared against lymphoscintigraphy (44%) and MRL (36%; p < 0.001 for both). The identified ultrasound imaging criteria for functioning lymph node were oval lymph node shape (Solbiati Index), morphology, vascularity pattern, and vascularity quantification.

CONCLUSION

 The use of ultrasound in nodal evaluation was proven effective in different pathologic conditions and demonstrated the best prediction for functionality of the lymph node based on the new evaluation criteria.

Breast Cancer-Related Lymphedema Assessed via Tissue Dielectric Constant Measurements

This review describes the use of tissue dielectric constant (TDC) measurements mainly in the assessment of breast cancer-related lymphedema (BCRL). PubMed, Web of Science, and EMBASE databases were initially searched using criteria that included the terms "dielectric" and "lymphedema." The initial search yielded a total of 131 titles. After removing studies not focused on upper extremity lymphedema, 56 articles remained. These articles, together with relevant articles from their bibliographies, formed the basis of the review. The findings show the potential utility and applications of TDC measurements to help detect and track BCRL, whether present in limbs, breasts, or trunks. It is reported as a non-invasive, simple-to-use method, with each measurement requiring less than 10 seconds, suggesting its practicality and useability as an in-office or in-clinic screening and tracking method. Although there are various ways to quantitatively evaluate lymphedema, most, if not all, are restricted to measurements on limbs. Thus, one significant advantage of the TDC approach is that almost any local region of interest can be effectively measured and tracked, which, for BCRL, could include specific regions of arms or hands, breasts, and truncal areas.

Comparative Analysis of Preoperative High Frequency Color Doppler Ultrasound versus MR Lymphangiography versus ICG Lymphography of Lymphatic Vessels in Lymphovenous Anastomosis

BACKGROUND

 Despite the extensive use of various imaging modalities, there is limited literature on comparing the reliability between indocyanine green (ICG) lymphography, MR Lymphangiogram (MRL), and high frequency color Doppler ultrasound (HFCDU) to identify lymphatic vessels.

METHOD

 In this study of 124 patients, the correlation between preoperative image findings to the actual lymphatic vessel leading to lymphovenous anastomosis (LVA) was evaluated. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and simple detection were calculated. Subgroup analysis was also performed according to the severity of lymphedema.

RESULTS

 Total of 328 LVAs were performed. The HFCDU overall had significantly higher sensitivity for identifying lymphatic vessels (99%) over MRL (83.5%) and ICG lymphography (82.3%)(p < 0.0001). Both ICG lymphography and HFCDU had 100% specificity and PPV. The NPV was 3.6%, 6.5% and 57.1% respectively for MRL, ICG lymphography, and HFCDU. All modalities showed high sensitivity for early stage 2 lymphedema while HFCDU showed a significantly higher sensitivity for late stage 2 (MRL:79.7%, ICG:83.1%, HFCDU:97%) and stage 3 (MRL:79.7%, ICG:79.7%, HFCDU:100%) over the other two modalities (p < 0.0001).

CONCLUSION

 This study demonstrated while all three modalities are able to provide good information, the sensitivity may alter as the severity of lymphedema progresses. The HFCDU will provide the best detection for lymphatic vessels throughout all stages of lymphedema. However, as each modality provides different and unique information, combining and evaluating the data according to the stage of lymphedema will be able to maximize the chance for a successful surgical outcome.

Imaging biomarkers for diagnosis and treatment response in patients with lymphedema

Lymphedema is defined as a dysfunction of the lymphatic system producing an accumulation of lymphatic fluid in the surrounding tissue, as well as edema and fibrosis. A total of 250 million people worldwide are affected by this condition. Greater than 99% of these cases are related to a secondary cause. As there is a lack of curative therapy, the goal involves early diagnosis, in order to prevent the progression of the disease. Additionally, early diagnosis can aid in decreasing the demand for more complex surgical procedures. Currently, there is an impressive breadth of diagnostic tests available for these patients. We aimed to review the available literature in relation to the utilization of imaging biomarkers for the early diagnosis and treatment response in lymphedema.

Patient-specific surgical options for breast cancer-related lymphedema: technical tips

In order to provide a physiological solution for patients with breast cancer-related lymphedema (BCRL), the surgeon must understand where and how the pathology of lymphedema occurred. Based on each patient's pathology, the treatment plan should be carefully decided and individualized. At the authors' institution, the treatment plan is made individually based on each patient's symptoms and relative factors. Most early-stage patients first undergo decongestive therapy and then, depending on the efficacy of the treatment, a surgical approach is suggested. If the patient is indicated for surgery, all the points of lymphatic flow obstruction are carefully examined. Thus a BCRL patient can be considered for lymphaticovenous anastomosis (LVA), a lymph node flap, scar resection, or a combination thereof. LVA targets ectatic superficial collecting lymphatics, which are located within the deep fat layer, and preoperative mapping using ultrasonography is critical. If there is contracture on the axilla, axillary scar removal is indicated to relieve the vein pressure and allow better drainage. Furthermore, removing the scars and reconstructing the fat layer will allow a better chance for the lymphatics to regenerate. After complete removal of scar tissue, a regional fat flap or a superficial circumflex iliac artery perforator flap with lymph node transfer is performed. By deciding the surgical planning for BCRL based on each patient's pathophysiology, optimal outcomes can be achieved. Depending on each patient's pathophysiology, LVA, scar removal, vascularized lymph node transfer with a sufficient adipocutaneous flap, and simultaneous breast reconstruction should be planned.

Lymph Node to Vein Anastomosis (LNVA) for lower extremity lymphedema

The microsurgical options for lower limb lymphedema is a challenge. In search to improve the overall result, we hypothesized it would be beneficial to add the functioning lymph nodes to vein anastomosis (LNVA) in addition to lymphovenous anastomosis (LVA). This is a retrospective study of 160 unilateral stage II & III lower extremity lymphedema comparing the outcome between the LNVA + LVA group and the LVA only group from May 2013 to June 2018. MRI was used to identify the functioning lymph nodes. Patient outcome, including lower extremity circumference, body weight, bio impedance test, and other data were analyzed to evaluate whether lymph nodes to vein anastomosis (LNVA) improved outcome. The LNVA + LVA group showed significantly better results for circumference reduction rate, body weight reduction rate, and extracellular fluid reduction rate of the affected limb as compared to the LVA only group for both stage II and III lymphedema. The MRI imaging revealed that 9 cases had no identifiable lymph nodes of the affected limb and 54 cases with a nonfunctioning lymph node upon exploration despite positive imaging. Correlation showed the lymph node size needed to be at least 8 mm in the MRI to be functional. The LNVA + LVA approach for lymphedema has the benefit of better reduction as compared to LVA alone in the lower limb as well as the suprapubic region. Preoperative MRI will help to identify the functioning lymph node by increasing the overall probability of positive outcome.